Tomas, My experience with switching power supplies has been that if they are noise makers they are Chinese made. I used to install a lot of Electronic asset control systems (anti-shoplifting) ; most of these devices work in the region of around 60 khz. Back when the gas discharge, fluorescent and halogen lamps were king in the retail business (lighting in stores) the noisy units were always Chinese made, 100% That is not to say that they do not produce low noise units, they do but most of what we ran into even high cost units had not filtering in the input stage to the switcher. So you have 60Hz hitting a diode now you have 60 Hz pulses going into a switcher switching at around 20 Khz, again very little filtering, What is the strongest harmonic in any nonlinear system? The 3rd, where did it fall?? about 60Khz (20X3) with side bands every 180hz above and below the center frequency of the 3rd harmonic out a couple of Khz each side of the harmonic. If they had just added a FEW capacitors most of this would not have been an issue. So this noisy hamonic fell right in the passband of the receivers. These things were not German (they made them) Italian (they to) nor other sources, they were Chinese. Sorry if the truth hurts that is the way it is. I have power supplies here at the house some of the switchers are very raw, when I find them I go in and add a cap or inductor and get rid of it.
Now with the LED lighting they have cleaned up their act to a certain extent but many of them are still lacking. This is my experience with these devices. Now laser diodes is another story... They do a good job on those. I have quite a few diode lasers and that is where they come from, in that case the vendors have taken the time to produce a good product for the price. Anytime I can pay $40 for a diode that will burn a hole in a sheetrock wall, I am happy with that diode. When I can get a diode that will last thousands of hours and put in a cielometer and never see the thing again I am happy. And these are all Chinese diodes, so the street runs both ways. That is my Heinz 57 varieties view of things. Sorry if I am blunt but I try to tell what I have found I gave you two of my experiences one bad one good. Both from the same source area. On Fri, Sep 25, 2020 at 12:01 AM <[email protected]> wrote: > On Thu, 2020-09-24 at 21:04 -0500, Chuck Hast wrote: > > > > <snip> > > > none of the others. Computer PSU's can be noisy also as can any > > (Chinese) switching power supply. > > > > > > I wonder, without any desire or starting political flame wars, what has > "Chinese" to do with any of this stuff? > > Are there any other power supplies other than the ones Made in China on > normal market? I cannot remember the last time I saw not Made in China > ATX/server power supply in retail or enterprise. I guess ASUS, FoxCon, > .... and other Taiwanese OEMs started as successful switching power > supply manufactures in the 80s, they were not "Chinese", but by the end > of 90s it is all Made in China AFAIK - so - what are you comparing > those Chinese power supply with? > > I do not believe that you meant to spark a pogrom, riot or something > ... - Still - Do we really need more of this kind of messaging, > especially these days. > > Just saying ... > > _______________________________________________ > PLUG: https://pdxlinux.org > PLUG mailing list > [email protected] > http://lists.pdxlinux.org/mailman/listinfo/plug > -- Chuck Hast -- KP4DJT -- I can do all things through Christ which strengtheneth me. Ph 4:13 KJV Todo lo puedo en Cristo que me fortalece. Fil 4:13 RVR1960 _______________________________________________ PLUG: https://pdxlinux.org PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
